Efficient Self-Assembly of Archaeoglobus fulgidus Ferritin around Metallic Cores

Swift, Joe; Butts, Christopher A.; Cheung-Lau, Jasmina C.; Yerubandi, Vijay; Dmochowski, Ivan J.

doi:10.1021/la8040743

Cited by 61 publications

(56 citation statements)

References 64 publications

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“…Several hydrophobic contacts were identified at subunit interfaces of the AfFtn and AfFtn-AA structures. AfFtn and its mutant showed a NaCl-mediated self-assembly in a dose-dependent manner, which suggests that hydrophobic interaction is the key force of the self-assembly of AfFtn subunits (20,22,25). In the presence of 150 mM NaCl, about 80% dimeric subunits of these ferritins reversibly self-assemble into cages, which could be potentially used for developing a drug delivery strategy.…”

Section: Resultsmentioning

confidence: 97%

The unique self-assembly/disassembly property of Archaeoglobus fulgidus ferritin and its implications on molecular release from the protein cage

Sana

Johnson

Lim

2015

Biochimica et Biophysica Acta (BBA) - General Subjects

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Please cite this article as: Barindra Sana, Eric Johnson, Sierin Lim, The unique self-assembly/disassembly property of Archaeoglobus fulgidus ferritin and its implications on molecular release from the protein cage, BBA -General Subjects (2015), doi: 10.1016/j.bbagen.2015 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTUnique iron mediated self-assembly/disassembly of A. fulgidus ferritin 2 Abstract:BACKGROUND: In conventional in vitro encapsulation of molecular cargo, the multi-subunit ferritin protein cages are disassembled in extremely acidic pH and re-assembled in the presence of highly concentrated cargo materials, which results in poor yields due to the low-pH treatment. In contrast, Archaeoglobus fulgidus open-pore ferritin (AfFtn) and its closed-pore mutant (AfFtn-AA) are present as dimeric species in neutral buffers that self-assemble into cage-like structure upon addition of metal ions.METHODS: To understand the iron-mediated self-assembly and ascorbate-mediated disassembly properties, we studied the iron binding and release profile of the AfFtn and AfFtn-AA, and the corresponding oligomerization of their subunits.RESULTS: Fe 2+ binding and conversion to Fe 3+ triggered the self-assembly of cage-like structures from dimeric species of AfFtn and AfFtn-AA subunits, while disassembly was induced by dissolving the iron core with reducing agents. The closed-pore AfFtn-AA has identical iron binding kinetics but lower iron release rates when compared to AfFtn. While the iron binding rate is proportional to Fe 2+ concentration, the iron release rate can be controlled by varying ascorbate concentrations.CONCLUSION: The AfFtn and AfFtn-AA cages formed by iron mineralization could be disassembled by dissolving the iron core. The open-pores of AfFtn contribute to enhanced reductive iron release while the small channels located at the 3-fold symmetry axis (3-fold channels) are used for iron uptake.GENERAL SIGNIFICANCE: The iron-mediated self-assembly/disassembly property of AfFtn offers a new set of molecular trigger for formation and dissociation of the protein cage, which can potentially regulate uptake and release of molecular cargo from protein cages.

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Section: Resultsmentioning

confidence: 97%

The unique self-assembly/disassembly property of Archaeoglobus fulgidus ferritin and its implications on molecular release from the protein cage

Sana

Johnson

Lim

2015

Biochimica et Biophysica Acta (BBA) - General Subjects

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“…AfFtn and AfFtn-AA Show Comparable Self-assembly PatternAfFtn has been shown to exist primarily as dimer and fully assembled 24-mer at 20 and 600 mM NaCl concentrations, respectively (10,29). Size exclusion chromatography and dynamic light scattering studies at different salt concentrations suggest that the selfassembly of AfFtn-AA is also dependent on ionic strength.…”

Section: Resultsmentioning

confidence: 99%

The Role of Nonconserved Residues of Archaeoglobus fulgidus Ferritin on Its Unique Structure and Biophysical Properties

Sana

Johnson

Maguères

et al. 2013

Journal of Biological Chemistry

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Background: Archaeoglobus fulgidus ferritin (AfFtn) assembles with unique tetrahedral symmetry and four large pores. Results: The AfFtn K150A/R151A double mutant forms a closed octahedral assembly with reduced iron release rates relative to the tetrahedral assembly. Conclusion: The K150A/R151A substitution alters the symmetry type of the ferritin cage. Significance: The AfFtn can be modulated for tuning molecular release from the cavity.

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“…At lower ionic strength ([NaCl] <200 mM), the protein disassembles into stable dimers, which we refer to herein as the protein subunits. 19,20 We have used the ionic strength-dependent self-assembly of AfFtn to encapsulate citrate- or bis( p -sulfonatophenyl)phenylphosphine (BSPP)-functionalized gold nanoparticles (AuNPs), rendering them more biocompatible and stable to salt-induced precipitation. 20–22 The encapsulation process happens under mild conditions, at room temperature with gentle agitation.…”

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confidence: 99%

Thermophilic Ferritin 24mer Assembly and Nanoparticle Encapsulation Modulated by Interdimer Electrostatic Repulsion

et al. 2017

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Protein cage self-assembly enables encapsulation and sequestration of small molecules, macromolecules, and nanomaterials for many applications in bionanotechnology. Notably, wild-type thermophilic ferritin from Archaeoglobus fulgidus (AfFtn) exists as a stable dimer of four-helix bundle proteins at low ionic strength, and the protein forms a hollow assembly of 24 protomers at high ionic strength (∼800 mM NaCl). This assembly process can also be initiated by highly charged gold nanoparticles (AuNPs) in solution, leading to encapsulation. These data suggest that salt solutions or charged AuNPs can shield unfavorable electrostatic interactions at AfFtn dimer-dimer interfaces, but specific “hot-spot” residues controlling assembly have not been identified. To investigate this further, we computationally designed three AfFtn mutants (E65R, D138K, A127R) that introduce a single positive charge at sites along the dimer-dimer interface. These proteins exhibited different assembly kinetics and thermodynamics, which were ranked in order of increasing 24mer propensity: A127R < WT < D138K ≪ E65R. E65R assembled to the 24mer across a wide range of ionic strengths (0 – 800 mM NaCl), and the dissociation temperature for the 24mer was 98 °C. X-ray crystal structure analysis of the E65R mutant identified a more compact, closed-pore cage geometry. A127R and D138K mutants exhibited wild-type ability to encapsulate and stabilize 5-nm AuNPs, whereas E65R gained ability to remain assembled in apo-form. This work illustrates designed protein cages with distinct assembly and encapsulation properties.

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Efficient Self-Assembly of Archaeoglobus fulgidus Ferritin around Metallic Cores

Cited by 61 publications

References 64 publications

The unique self-assembly/disassembly property of Archaeoglobus fulgidus ferritin and its implications on molecular release from the protein cage

The unique self-assembly/disassembly property of Archaeoglobus fulgidus ferritin and its implications on molecular release from the protein cage

The Role of Nonconserved Residues of Archaeoglobus fulgidus Ferritin on Its Unique Structure and Biophysical Properties

Thermophilic Ferritin 24mer Assembly and Nanoparticle Encapsulation Modulated by Interdimer Electrostatic Repulsion

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